Common vehicles such as automobiles are equipped with a lighting device (headlamp, headlight, etc.) configured to brighten the surroundings (in particular, areas in the forward direction in which a vehicle travels). Vehicle headlamps mainly include a light source configured to emit white light, a projection optical system configured to magnify light emitted from the light source and project the same, and a housing configured to support these components.
In recent years, in the technical field of vehicular headlamps, attention has been paid to a technique for controlling a light distribution pattern in real time in accordance with a situation in front, that is, presence or absence of an oncoming vehicle, a preceding vehicle, and a position thereof. Such a technique is known as an adaptive driving beam (ADB) system. In addition, headlamp systems (called AFS, adaptive front-lighting system, etc.) configured to adjust a light distribution in the traveling direction in accordance with the steering angle of the steering wheel are becoming popular. Liquid crystal elements can be adopted as a light distribution control element for ADB and AFS (see, for example, Japanese Patent Application Laid-Open No. Hei. 06-191346).
Note that when a semiconductor light-emitting element (LED element) is used as the light source, the light source usually generates heat and becomes high temperature. In such a case, it is preferable to provide a blower fan configured to cool the light source (see, for example, Japanese Patent Application Laid-Open No. 2014-056792).